In the fish-farming industry a common practice while transferring organisms between receptacles is to make an estimation of the number and size of organisms being transferred. Various methods are used to count the organisms. As an example NO168151 (Kvassheim) discloses a method and device for the recording of number of objects, particularly live fish, were a CCD-line camera is used to count organisms on the basis of their area. NO332233 (Wingan) also discloses a fish counter where two cameras are positioned perpendicular to each other. None of these documents disclose a solution similar to the one described herein.
It is a commonly used technique when counting live fish in counting equipment for fish to position a camera between the stream of fish and a light source. The organisms then generate silhouettes that the camera registers. The signals from the camera are processed in a computer that turns the data into information on the number of organisms by using a specific algorithm.
When scaling up the size of equipment used in fish-farming industries for sorting and counting organisms it is a disadvantage that the distance of the camera from the light source, as described above, has to be enlarged in order for the camera to get a sufficient field of vision. The larger the equipment gets, the bigger the distance has to be.